Lady beetles: useful insect or pest?

September 1st, 2023

Lady beetles (or ladybugs as some people call them) are useful outside, but, when they come indoors in large numbers, they become a real nuisance! Who's the culprit? The Asian Lady Beetle!

Lady beetles are often used in the fight against aphids. An adult consumes between 90 and 270 aphids per day, and larvae eat between 600 and 1,200 during their development. Aphids are daunting enemies in our gardens, which makes lady beetles a gardener's best friend!

Nevertheless, when these insects arrive en masse in homes in late September, they become pests. They look for structural voids where they can group together in great numbers to hibernate. When the temperature warms up, they gather at windows, attracted by the light. Inevitably, part of the population cannot find its way back outside in the spring. Their carcasses accumulate, attracting larder beetles, who take up residence, eventually finding their way into the various rooms of your home.

Thus, it is important to prevent lady beetles from entering our buildings. Because they are such useful insects, physical exclusion methods are best: seal cracks around doors, windows, walls, pipes, and electric cables; repair screens; etc. If they still get into the house, sweep them up with a broom and release them outside, as far away from the house as possible.

If effective sealing is impossible and you don't want them inside, an insecticide, like that used for cluster flies, can be applied outside. This should be used only as a last resort because, after all, lady beetles are very handy to have around!

The Technical Team

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